Auxiliary switch for molded-case circuit breaker

ABSTRACT

A molded-case circuit breaker is provided with a separate compartment containing an auxiliary switch. The switch may be constructed and arranged to be in an open condition when the circuit breaker is ON, and connected in series with a remote warning device activated upon tripping of the circuit breaker and closing of the switch, or it may be constructed and arranged to be in a closed condition when the circuit breaker is ON, and connected in series with a remotely energizable shunt trip coil provided in the separate compartment and deenergized upon tripping of the circuit breaker and opening of the switch.

United States Patent [191 Layton et al.

[in 3,820,046 [4 June 25, 1974 AUXILIARY SWITCH FOR MOLDED-CASE CIRCUITBREAKER [75] Inventors: Beryl W. Layton; William J.

Weaver, both of Cedar Rapids, Iowa [73] Assignee: Square D Company, ParkRidge, Ill. [22] Filed: Oct. 15, 1973 [2i] Appl. No.: 406,729

52 US. Cl. 335/13, 335/25 [51] Int. Cl. HOlh 71/46 [58] Field of Search335/13, 17, 25

[56] References Cited UNITED STATES PATENTS 3,264,428 8/1966 Hollyday335/25 3,340,375 9/1967 Kiesel et al. 335/17 3,436,695 4/1969Dessert..... 335/13 3,530,412 9/1970 Gryctko.... 335/13 PrimaryExaminer-Harold Broome Attorney, Agent, or Firm-Harry G. Thibault;Harold J. Rathbun 5 7] ABSTRACT A molded-case circuit breaker isprovided with a separate compartment containing an auxiliary switch. Theswitch may be constructed and arranged to be in an open condition whenthe circuit breaker is ON, and connected in series with a remote warningdevice activated upon tripping of the circuit breaker and closing of theswitch, or it may be constructed and arranged to be in a closedcondition when the circuit breaker is ON, and connected in series with aremotely energizable shunt trip coil provided in the separatecompartment and deenergized upon tripping of the circuit breaker andopening of the switch.

5 Claims, 11 Drawing Figures PATENTEDJUNZS m4 SHEET 3 0F 4 FIG.IO

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PATENTEDJUH 25 I974 SHEET UF 4 AUXILIARY SWITCH FOR MOLDED-CASE CIRCUITBREAKER This invention relates to an auxiliary switch for a molded-casecircuit breaker. In the preferred embodiment, the switch is closed whenthe circuit breaker is ON, is connected in series with a shunt tripcoil, and is opened upon tripping of the circuit breaker. If tripping ofthe circuit breaker is the result of persistent conditions which wouldcause continuous energization of the shunt trip coil, the opening of theauxiliary switch would prevent the coil from burning out. In a modifiedversion, the switch is open when the circuit breaker is ON, is connectedin series with a remote warning device, and is closed upon tripping ofthe circuit breaker.

A principal object of the invention is to provide an auxiliary switch asprotection means for a shunt trip coil of a molded-case circuit breaker.

Other objects and advantages will become apparent when the followingspecification is considered along with the accompanying drawings inwhich:

FIG. 1 is an end elevational view of a single-pole molded-case electriccircuit breaker constructed in accordance with the invention andincluding a separate compartment for auxiliary devices;

FIG. 2 is a sectional view taken generally along the line 2-2 of FIG. 1and showing a circuit breaker mechanism in an ON condition;

FIG. 3 is a sectional view taken generally along the line 3-3 of FIG. 1and showing-a partition wall between compartments;

FIG. 4 is a sectional view taken generally along the line4-4 of FIG. 1and showing auxiliary devices in the separate compartment;

FIG. 5 is a fragmentary perspective view of portions of an auxiliaryswitch of FIG. 4, taken generally in the direction of arrows 5-5;

FIG. 6 is a fragmentary sectional view taken generally along the'line6-6 of FIG. 4 and showing an end portion of a shunt trip coil and anactuating core member;

FIG. 7 is a perspective view, with portions broken away, of certainparts of FIG. 6;

FIG. 8 is a front view of a modified single-pole molded-case electriccircuit breaker constructed in accordance with the invention andincluding a separate compartment for auxiliary devices;

FIG. 9 is a sectional view taken along the line 9-9 of FIG. 8 andshowing auxiliary devices in the separate compartment;

FIG. 10 is a fragmentary sectional view showing a modification of theauxiliary switch of FIG. 4; and

FIG. 11 is a fragmentary perspective view of portions of the auxiliaryswitch of FIG. 10.

In accordance with the invention and as shown in FIG. 1, a casingportion forms a separate compartment for auxiliary devices and a casingportion 22 houses a single-pole circuit breaker having a mechanismsimilar to that shown in U.S. Pat. No. 2,902,560, to which reference maybe had for a more complete description. The present invention is notconfined to single pole circuit breakers but may also be incorporated inmulti-pole molded-case electric circuit breakers such as disclosed inUS. Pat. No. 2,889,428.

The circuit breaker mechanism of the casing portion 22 is shown in FIG.2 and includes a plug-in type line terminal member 28 having astationary contact 29 secured to an inner end portion thereof, apivotally mounted reciprocable operating handle 30, a movable contactarm 32 pivotally mounted adjacent one end in a pair of spaced dependingleg portions of the handle 30 and having a movable contact 33 adjacentthe other end, a releasably latchable trip lever 34 pivotally mounted ona pin portion 35 of the casing portion 22, a tension spring 36 connectedadjacent one end to the contact arm 32 and adjacent the other end to thetrip lever 34, a load terminal strap 38 provided with a clamping screw39, a bi-metallic strip 40 attached adjacent one end to an inner end ofthe strap 38 and having a generally U-shaped magnetizable core 42secured to its other end portion, a braided conductor 44 having one endportion secured between the bi-metallic strip 40 and the core 42 and itsother end portion secured to the contact arm 32, an armature member 46pivotally mounted on the core 42 and releasably latching the trip lever34, a compression spring 48 biasing the annature 46 away from the core42, a generally U-shaped ambient temperature compensating bimetallicmember 50 having one leg portion secured to the armature 46 and itsother leg portion loosely overlapping the core 42, a calibrating screw52 for resiliently deforming the terminal strap 38 to vary the amount oflatching engagement between the trip lever 34 and the armature 46, amounting clip 54 opposite the line terminal 28, a stack 56 of arcsuppressing plates adjacent the contacts 29 and 33, an arc shield 58 ofinsulating material hooked to the movable contact arm 32, a pin 60carried by the trip lever 34 and cooperable with the handle 30 to effectthe relatching of the trip lever, and a bent tab portion 62 of the triplever 34 adjacent a pivotally mounted trip bar 76 and an armatureactuating first crank member 66 when the trip lever is in a latchedposition, and engageable, on movement of the trip lever away from thelatched position, with an outer end portion of the first crank member66. The tab 62 also retains a biasing spring 68 connected to anindicating member 70, the indicator 70 being movable into an exposedposition with respect to a viewing window 72 in an upper wall of thecasing portion 22 when the trip lever 34 is moved to the trippedposition.

On the flow of a sustained moderate overload current through thebimetallic strip 40 of the circuit breaker mechanism of the casingportion 22, deflection thereof causes counterclockwise (as viewed inFIG. 2) movement of the core 42, ambient temperature compensating member50, and armature 46 about the upper end of the bimetallic strip 40 andreleases the trip lever 34. Also, upon flow of a high fault currentthrough the bimetallic strip 40 of the circuit breaker mechanism, thearmature 46 is attracted toward the core 42 and releases the trip lever34. The trip lever 34 of the circuit breaker mechanism is thus providedwith a thermally and magnetically responsive tripping means includingthe bimetallic strip 40, core 42, armature 46, and bimetallic member 50.

The casing portion 20 is connected to the casing portion 22, with anintermediate wall portion 24 therebetween, by appropriate fasteningmeans and the compartments in the two casing portions are traversed bythe trip bar 76 on which the first crank member 66 in the casing portion22 and a second crank member 66 in the casing portion 20 are mounted.

The release of the trip lever 34 of the circuit breaker mechanism,biased clockwise (as viewed in FIG. 2) by the spring 36, causes movementof the upper end of spring 36 to the opposite side of the pivotalconnection between the contact arm 32 and the handle 30, to effectdisengagement of the movable contact 33 from the stationary contact 29.The release of the trip lever 34 also causes movement of the tab 62 intoengagement with the first crank member 66 to effect pivotal movementthereof counterclockwise (as viewed in FIG. 2), and, through the tripbar 76, to also effect pivotal movement of the second crank member 66inthe casing portion 20.

As shown in FIG. 4, the casing portion forms a compartment forelectromagnetically operable actuating means for effecting movement ofthe latching armature member 46 to release the trip lever 34 of thecircuit breaker mechanism of the casing portion 22, the actuating meansincluding a generally U-shaped magnetizable frame 82 having a bightportion 82a and a pair of spaced parallel leg portions 82b and 820. Asolenoid or trip coil 84 mounted within the frame 82 has a reciprocableactuating core member 85. Mounted opposite the bight portion 82aadjacent the free end portions of the leg portions 82b and 820 is aguide plate 86 having an opening therein which receives one end of thecore member 85. An opposite end of the core member 85 passes through ahole in the bight portion 82a of the frame 82. An elongated actuatingtab 87 is suitably secured to the end of the core member passing throughthe bight portion of the frame 82, as by a rivetlike portion 88 bestshown in FIG. 7. A biasing spring 89 mounted in the casing portion 20biases the actuating tab 87 and core member 85 toward the right in FIG.4. The free end portion of the tab 87 extends through an opening 79(FIG. 3) in the intermediate wall portion 24 into cooperativerelationship with the ambient temperature compensating bimetallic member50, which is connected to the armature 46. When the trip coil 84 isenergized, the tab 87 strikes the bimetallic member 50 to drive thearmature 46 toward the core 42 and release the trip lever 34 to trip thecircuit breaker mechanism of the casing portion 22. The end of the coremember 85 adjacent the guide plate 86 has a peripheral ring 85a to limitits travel.

Terminals 90 and 91 on the casing portion 20 are connectable to anexternal circuit for energizing the coil 84. Thus the coil 84 can beenergized from a remote location to trip the circuit breaker mechanismof the casing portion 22.

In accordance with this invention, the casing portion 20 has a switch 92provided therein as shown in the upper right-hand comer of FIG. 4 and inFIG. 5. The switch 92 comprises a pair of contacts in the form offlexible resilient contact fingers 93 and 94 which are normally open. Aswitch operating member or lever 95 includes a triangular plate 96having an upper surface and a lower surface (the terms upper and lowerreferring specifically to the orientation of the plate 96 as shown inFIG. 5), a driving pin 96a extending perpendicularly from the uppersurface of the plate 96 at one of the vertices thereof, and a switchoperating pin 96b and a mounting pin 96c extending respectively from thelower surface of the plate 96 at the remaining two vertices thereof. Themounting pin 96c is pivotally mounted in a hole 98 in the casing portion20. The switch operating pin 96b is engageable with the contact finger93 of the switch 92. The driving pin 96a extends through a hole 99 (FIG.3) in the intermediate wall portion 24 and is engageable with a surface97 (FIG. 2) of the operating handle 30 of the circuit breaker mechamsm.

When the circuit breaker handle is moved to the ON position, the drivingpin 96a cooperates with the surface 97 of the operating handle 30 of thecircuit breaker to pivot the plate 96 counterclockwise about themounting pin 960 as viewed in FIGS. 4 and 5, the switch operating pin96b moving contact finger 93 into engagement with the contact finger 94.Thus, when the circuit breaker handle 30 is in the ON position, theswitch 92 is closed. 7

With the switch 92 closed, a current path exists from the terminal 91,through the contact fingers of the switch 92 and the coil 84 to theterminal 90. When a circuit is completed at a remote location, currentflow through the coil 84 actuates the core member to cause the tab 87 topush the bimetallic member 50 and drive the armature 46 of the circuitbreaker mechanism of the casing portion 22 toward the core 42 to releasethe trip lever 34.

The release of the trip lever 34 causes movement of the tab 62 intoengagement with the first crank member 66 of the circuit breaker 22 toaffect pivotal movement thereof counterclockwise as viewed in FIG. 2.The movement of the first crank member 66 is transmitted through thetrip bar 76 to effect pivotal movement of the second crank member 66 inthe casing portion 20 clockwise as viewed in FIG. 4, moving the secondcrank member 66 into engagement with the contact finger 94 of the switch92 and moving the contact finger 94 out of engagement with the contactfinger 93 to hold the switch open when the circuit breaker mechanism ofthe casing portion 22 is in the tripped condition. Thus the switch 92 isheld open by the second crank member 66 when the circuit breaker is inthe tripped condition and the switch 92 remains open regardless of theposition of the switch operating lever 95.

A second embodiment of the present invention is disclosed in FIGS. 8 and9 in which a casing portion 101, a wall portion 102, and a casingportion 103 are secured together. The casing portion 103 houses acircuit breaker mechanism such as that disclosed in U.S. Pat. No.3,061,697. The casing portion 101 has a switch 104 therein havingnormally open contacts 108 and 109. A switch operating lever 110includes a plate 111 having a front surface and a rear surface (theterms front and rear refer specifically to the orientation of the leveras shown in FIG. 9), a driving pin 111a extending perpendicularly fromthe front surface of the plate 111 at a vertex thereof, and a switchoperating pin lllb and a mounting pin lllc extending from the rearsurface of the plate 111 at respective vertices thereof. The mountingpin lllc is pivotally mounted in a hole in the casing portion 101. Theswitch operating pin lllb is engageable with the contact 108 of theswitch 104. The driving pin 111a extends through an opening (not shown)in the wall portion 102 to engage a surface of one of a pair of togglelinks (not shown) of the operating mechanism of the circuit breaker inthe casing portion 103.

When the circuit breaker handle is moved to the ON position, the drivingpin 111a cooperates with the toggle link of the circuit breakermechanism in the casing portion 103 to pivot the plate 111 about themounting pin lllc, the switch operating pin 11 1b moving the contact 108into engagement with the contact 109 to close the switch 104. Thus whenthe handle of the circuit breaker in the casing portion 103 is in the ONposition, the switch 104 is closed.

With the switch 104 closed, a current path exists from a terminal 112 onthe casing portion 101, through the switch 104 and a coil 115, to asecond terminal 114 on the casing portion 101. When a circuit iscompleted at a remote location, current flow through the coil 115actuates a reciprocable actuating core member 116 which unlatches a triplever (not shown) of the circuit breaker in the casing portion 103 tomechanically trip the circuit breaker in a manner similar to thatdescribed above for the circuit breaker in the casing portion 22.

When the circuit breaker in the casing portion 103 is mechanicallytripped, a trip bar 117, similar to the trip bar 76 in the casingportions 20 and 22, is pivotally rotated to effect pivotal movement of acrank member 118 in the casing portion 101. The pivotal movement of thecrank member 118 moves the contact 109 out of engagement with thecontact 108 and holds the switch open when the circuit breaker in thecasing portion 103 is in the tripped condition. Thus the switch 104 isheld open by the crank member 118 when the circuit breaker is in thetripped condition and the switch 104 remains open regardless of theposition of the switch operating lever 110.

The switch actuating levers 95 and 110 may also be used to operateauxiliary switches similar to the switches 92 and 104 but modified toactivate an alarm, in a system without a shunt trip coil, as a signalthat the circuit breaker is OFF or TRIPPED. Such a modified switch 120is shown in FIGS. and 11 in conjunction with the switch operating lever95. The switch 120 includes a pair of flexible resilient contact fingers122 and 124, the contact 124 having a generally U-shaped free endportion including a leg portion 125 and the free end portion of thecontact 122 being disposed within the U-shaped portion of the contact124 and normally engaging the inner side of the leg portion 125.

Operation of the switch 120 is as follows. When the circuit breaker isclosed to ON condition, the driving pin 96a of the lever 95 is driven bythe surface 97 (FIG. 2) on the breaker handle 30, which causes theswitch operating pin 96b to deflect the contact 122 away from the legportion 125 of the contact 124, thus opening the switch 120. When thecircuit breaker is tripped, the crank member 66 pushes the contact 124downwardly as viewed in FIG. 10 to re-establish contact between the legportion 125 and the contact 122, which closes the switch 120 to completean alarm circuit, regardless of the position of the lever 95. When thecircuit breaker is reset and left in OFF condition, the lever 95 isreturned to its normal position by the resiliency of the contact 122,allowing the contact 122 to resume its normal engagement with the legportion 125 of the contact 124, which also closes the switch 120 tocomplete an alarm circuit.

The switch 120 could be designed to be closed only when the circuitbreaker of the casing portion 22 is in the tripped condition. Thecontact 122 could be formed so that in its normal or free position itwould not touch any part of the contact 124, particularly the legportion 125, and the switch lever 95 could be omitted. Then theoperation of the switch would consist only of the crank member 66pushing the contact 124 downwardly as viewed in FIG. 10 when the breakertrips. This would cause the contact 122 to engage the leg portion 125 ofthe contact 124, closing the switch 120. In ON and OFF conditions of thecircuit breaker, there would be no contact between contacts 122 and 124.

Various modifications may be made in the structure disclosed withoutdeparting from the spirit and scope of the invention as set forth in theappended claims.

We claim:

1. An electric circuit breaker comprising:

a. a molded case having a plurality of compartments;

b. a circuit breaker mechanism in one of the compartments including apair of separable contacts, a releasably latchable trip lever releasablefrom a latched position to effect separation of the contacts, andthermally and electromagnetically operable tripping means operable toeffect release of the trip lever and separation of the contacts;

c. an operating handle pivotally mounted in the case, operativelyconnected to the contacts, and movable to an ON position to close thecontacts and to an OFF position to open the contacts;

d. an auxiliary switch including a pair of resiliently flexible contactfingers disposed in another of the compartments and having one operatingcondition in which the contact fingers are in engagement with each otherand another operating condition in which the contact fingers are out ofengagement with each other;

. a switch operating member pivotally mounted in said other of thecompartments, operatively engaged with a first of the contact fingers,and operatively engageable with the operating handle;

f. a trip bar mounted for pivotal movement in the case and traversingthe compartments;

g. a first crank member mounted on the trip bar in said one of thecompartments for rotary movement unitarily therewith upon operation ofthe tripping means; and

h. a second crank member mounted on the trip bar in said other of thecompartments for rotary movement unitarily therewith and operativelyengageable with a second of the contact fingers, the first contactfinger being flexed by the switch operating member to place theauxiliary switch in one of the operating conditions upon movement of theoperating handle to the ON position, and the second contact finger beingflexed by the second crank member to place the auxiliary switch in theother of the operating conditions upon operation of the tripping means.

2. An electric circuit breaker as claimed in claim 1 wherein the contactfingers are constructed and arranged in a manner such that the switchoperating member flexes the first contact finger out of engagement withthe second contact finger upon movement of the operating handle to ONposition and the second crank member flexes the second contact fingerinto engagement with the first contact finger upon operation of thetripping means.

3. An electric circuit breaker as claimed in claim 1 wherein the contactfingers are constructed and arranged in a manner such that the switchoperating member flexes the first contact finger into engagement thetripping means in said one of the compartments.

5. An electric circuit breaker as claimed in claim 1 wherein the switchoperating member includes a plate portion having a driving pin extendingfrom one side into operative engagement with the operating handle, and amounting pin and a switch operating pin extending from the other side,the mounting pin being pivotally mounted in the case and the switchoperating pin being operatively engaged with the first contact finger. k

1. An electric circuit breaker comprising: a. a molded case having aplurality of compartments; b. a circuit breaker mechanism in one of thecompartments including a pair of separable contacts, a releasablylatchable trip lever releasable from a latched position to effectseparation of the contacts, and thermally and electromagneticallyoperable tripping means operable to effect release of the trip lever andseparation of the contacts; c. an operating handle pivotally mounted inthe case, operatively connected to the contacts, and movable to an ONposition to close the contacts and to an OFF position to open thecontacts; d. an auxiliary switch including a pair of resilientlyflexible contact fingers disposed in another of the compartments andhaving one operating condition in which the contact fingers are inengagement with each other and another operating condition in which thecontact fingers are out of engagement with each other; e. a switchoperating member pivotally mounted in said other of the compartments,operatively engaged With a first of the contact fingers, and operativelyengageable with the operating handle; f. a trip bar mounted for pivotalmovement in the case and traversing the compartments; g. a first crankmember mounted on the trip bar in said one of the compartments forrotary movement unitarily therewith upon operation of the trippingmeans; and h. a second crank member mounted on the trip bar in saidother of the compartments for rotary movement unitarily therewith andoperatively engageable with a second of the contact fingers, the firstcontact finger being flexed by the switch operating member to place theauxiliary switch in one of the operating conditions upon movement of theoperating handle to the ON position, and the second contact finger beingflexed by the second crank member to place the auxiliary switch in theother of the operating conditions upon operation of the tripping means.2. An electric circuit breaker as claimed in claim 1 wherein the contactfingers are constructed and arranged in a manner such that the switchoperating member flexes the first contact finger out of engagement withthe second contact finger upon movement of the operating handle to ONposition and the second crank member flexes the second contact fingerinto engagement with the first contact finger upon operation of thetripping means.
 3. An electric circuit breaker as claimed in claim 1wherein the contact fingers are constructed and arranged in a mannersuch that the switch operating member flexes the first contact fingerinto engagement with the second contact finger upon movement of theoperating handle to ON position and the second crank member flexes thesecond contact finger out of engagement with the first contact fingerupon operation of the tripping means.
 4. An electric circuit breaker asclaimed in claim 3 including a shunt trip coil in said other of thecompartments and an actuating core member disposed within the coil andmounted for reciprocal movement, the coil being serially connected tothe auxiliary switch and the actuating core member being operativelyconnected to the tripping means in said one of the compartments.
 5. Anelectric circuit breaker as claimed in claim 1 wherein the switchoperating member includes a plate portion having a driving pin extendingfrom one side into operative engagement with the operating handle, and amounting pin and a switch operating pin extending from the other side,the mounting pin being pivotally mounted in the case and the switchoperating pin being operatively engaged with the first contact finger.